1. Field of the Invention
The present invention relates to a method and an apparatus for inspecting a laminated iron core configured by a plurality of laminated iron core pieces having a predetermined shape and including therein a cooling flow path allowing refrigerant to flow therethrough.
2. Description of the Related Art
A rotor of a motor or a generator has a problem that a permanent magnet is demagnetized due to the increased temperature of the rotor during rotation, thereby reducing the motor performance.
To cope with this problem, the rotor is cooled using refrigerant such as cooling oil. In addition to a hole formed to penetrate in the axial direction, a penetration hole extending from a shaft hole in the radial direction is used as a cooling flow path for the refrigerant. Here, the permanent magnet is easy to increase in temperature due to accumulated heat in the longitudinal-direction central area. Thus, by cooling the longitudinal-direction central area of the permanent magnet with a higher priority, the cooling efficiency can be enhanced (see, for example, JP-A-2014-176235 and JP-A-2013-027100 as Patent Documents 1 and 2).
Patent Document 1: JP-A-2014-176235
Patent Document 2: JP-A-2013-027100